Information on Business Segments - Total Assets and Customer Advances and Amounts In Excess Of Costs Incurred For Each Business Segment (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Assets	$ 44,876	$ 46,620
Operating Segments
Segment Reporting Information [Line Items]
Assets	37,230	35,822
Operating Segments | Aeronautics
Segment Reporting Information [Line Items]
Assets	8,435	7,713
Operating Segments | Missiles and Fire Control
Segment Reporting Information [Line Items]
Assets	5,017	4,577
Operating Segments | Rotary and Mission Systems
Segment Reporting Information [Line Items]
Assets	18,333	18,292
Operating Segments | Space
Segment Reporting Information [Line Items]
Assets	5,445	5,240
Corporate activities
Segment Reporting Information [Line Items]
Assets	$ 7,646	$ 10,798